As I reported yesterday on Search Engine Land, Google announced they are launching a new search algorithm penalty, to demote mobile pages that have "intrusive" interstitials that get in the users way.

Google said this new algorithm will launch on January 10, 2017 and will try to make these pages "not rank as highly" as they once did. This is actually replacing the app interstitials ad penalty that launched in September 2015. So that penalty is going away but it should cover and have the same impact on app interstitials ads.

How do you know if your interstitials are going to cause your web pages to rank lower? Google said if the interstitial "make content less accessible to a user." Here are the examples Google gave:

Showing a popup that covers the main content, either immediately after the user navigates to a page from the search results, or while they are looking through the page.

Displaying a standalone interstitial that the user has to dismiss before accessing the main content.

Using a layout where the above-the-fold portion of the page appears similar to a standalone interstitial, but the original content has been inlined underneath the fold.

But not all interstitials are bad, Google said these "would not be affected by the new signal."

Interstitials that appear to be in response to a legal obligation, such as for cookie usage or for age verification.

Login dialogs on sites where content is not publicly indexable. For example, this would include private content such as email or unindexable content that is behind a paywall.

Banners that use a reasonable amount of screen space and are easily dismissible. For example, the app install banners provided by Safari and Chrome are examples of banners that use a reasonable amount of screen space.

Google also updated the Search Console mobile usability report to take into account the change to the app interstitial ad penalty change. Google wrote:

App install interstitials will no longer trigger an error in the Mobile Usability report; therefore, you may see a drop in errors in this report. However, although no longer reported as an error, the presence of all types of intrusive interstitials are used as a ranking factor for pages in mobile search results.

By far, most users and webmasters are incredibly happy with this news. A WebmasterWorld thread has some of these comments, "about friggin time way overdue." But not everyone agrees, or at least they are calling what Google says versus what they practice hypocritical. One user said, "Adsense has been pushing "Page level ads" - anchor/overlay ads and full-screen "vignette ads" for months. Are these going to compromise rankings? Or not?"

But overall, most people are happy with this announcement and Google is giving people plenty of time to make the changes they need to make. If only there was a testing tool to confirm your interstitial is good and not bad...